Compass and Magnetic Declination question

[daz]

I have a compass with a rotating bezel that I can use to off set the magnetic declination - or so it says! I have found a site which I can look up the declination of a given location, but its what to do after that.

I think I:

1. Look up the Declination from http://www.nearby.org.uk/gma_calc.cgi (e.g. Kielder is 3.9 degrees WEST of North)

2. If the deviation is WEST then SUBTRACT the deviation from North, and rotate bezel 4 degrees to the WEST (in this example)

3. If the deviation is EAST then ADD the deviation to North, and rotate bezel to the EAST

So, I now have two markers - the compass marker pointing to magnetic north, and the bezel marker pointing to approx true north.

My question is how do I align my tripod??

Its a simple answer I'm sure, but I can't see it!! Just don't asl me for directions, OK!!!

[Talitha]

Probably geographic north.. not geomagnetic north.

[Dave Smith]

You need your tripod to point True North (i.e. geographic north as Carol says). You should end up with your tripod pointing 4 degrees East from the direction of your compass. i.e. the compass direction is 4 deg W of true N.

You've always got the pole star.

HTH

Dave

[daz]

Thanks guys. *Think* I have it!!

Dave - its for daylight setting up, hopefully to speed up the alignment process!!

[Paxo]

Don't worry too much Daz, there's an RAF beacon on the hill due north of the campsite (can be seen from the leccy field), align on that and you'll be reasonably close.

Steve

[Tinkerbell]

Lo Daz

For daytime alignment at Kielder, just point it at the big tree to the left of the little tree which is to the right and up a bit from the pine tree, You can't go wrong, just stick with Me I know these things. :scratch:

:withstupid: :laughing3: :withstupid: :laughing3: :withstupid: :laughing3:

[thing]

It's magnetic variation you're setting, not declination. different thing. Remember EAST is LEAST, WEST is BEST.

[Paxo]

Lo Daz

For daytime alignment at Kielder, just point it at the big tree to the left of the little tree which is to the right and up a bit from the pine tree, You can't go wrong, just stick with Me I know these things. :scratch:

:withstupid: :laughing3: :withstupid: :laughing3: :withstupid: :laughing3:

Don't tell everyone the local secrets Kevin!

Steve

[daz]

Pine tree. Check.

RAF Beacon. Check.

Thing. Thanks for the correction - but what does the last bit mean?? :scratch:

>starting to need a lie down now<

[Psychobilly]

http://en.wikipedia.org/wiki/Magnetic_declination

[thing]

Pine tree. Check.

RAF Beacon. Check.

Thing. Thanks for the correction - but what does the last bit mean?? :scratch:

>starting to need a lie down now<

Lets say you were flying on compass heading of 225 degrees, the mag var is 5 degrees east. EAST is LEAST means that to fly on a true heading of 225 you must fly compass heading 220. Vice versa for west. It's just an easy way of remembering how to apply your deviation card when you're flying. Having said that we always fly to magnetic headings rather than true headings.

Magnetic declination, contrary to Billy's Wilkpedia post is the angle your compass needle would make if it was free in all three axes. IE it would point to mag north but also at a considerable angle downwards. It can affect a compass around the equator point quite a bit unless the bearings are very good.

[Paxo]

Dave,

This is still commonly known as magnetic declination, and on-line tables quote as such.

Steve..

[thing]

What is? Magnetic variation? Depends on your background I think. I spent 22 years in the RAF, teaching navigation at one point. It's always referred to as magnetic variation in flying, and declination is the angle the compass needle would take if it were free to point where it wanted. Just different meanings in civvy street probably.

[Paxo]

I think maritime folk use 'magnetic declination' but I may be wrong.

Steve

[thing]

Interesting. I'll ask my cousin when I get the chance, she's in the Navy.